Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Quercus fusiformis

Quercus douglasii

escarpment live oak, live oak, plateau oak, Texas live oak

blue oak
Habit Trees, sometimes shrubs, subevergreen, trees to 25 m, shrubs often forming large clonal stands. Trees, deciduous, with single trunks, sometimes with few to several trunks.
Bark

dark brown or black, scaly.

gray, scaly.
Twigs

light gray, 1.5-3 mm diam., tomentulose, tomentulum often persistent in age.

reddish or yellowish, ca. 2 mm, densely or sparsely puberulent, occasionally glabrate with age.
Buds

reddish or dark brown, subglobose or ovate, 1.5-3 mm;

scale margins glabrous or puberulent.

reddish brown, rarely yellowish, broadly ovoid to rarely subglobose, (2-)3-5 mm;

scales glabrous except for ciliate margins, sometimes sparsely or densely pubescent.
Leaves

blade oblong-elliptic to narrowly ovate or lanceolate, sometimes obovate, ± planar, (10-)35-90(-150) × (15-)20-40(-85) mm, base rounded to truncate or cordate, rarely cuneate, margins minutely revolute or flat, entire or irregularly 1-3 toothed on each side, teeth mucronate (rarely spinose in suckers or juveniles), secondary veins obscure, 8-10 on each side, apex obtuse-rounded or acute;

surfaces abaxially whitish or glaucous, densely covered with minute, appressed, fused-stellate hairs, light green and glabrate in shade leaves, adaxially dark or light green, glossy, glabrous or with minute, scattered, stellate hairs.

blade obovate or elliptic, oblong or oblanceolate, (20-)40-60(-80) × (15-)20-30(-40) mm, base rounded-attenuate or rounded, rarely cuneate, margins shallowly lobed or irregularly toothed, sometimes entire, lobes mucronate or rounded, secondary veins 6-10 on each side, apex rounded, rarely moderately acute;

surfaces abaxially light green or blue-green, waxy, with scattered to crowded, semi-erect, (2-)4-6(-8)-rayed stellate hairs usually 0.2-0.6 mm diam. or larger, adaxially blue-green, glaucous or grayish, vestiture similar to abaxial surface.
Acorns

1-3, on peduncle 3-30 mm;

cup funnel-shaped, hemispheric, or deeply goblet-shaped, 8-15 mm deep × 6-12(-15) mm wide, base often constricted, scales whitish or grayish, thickened basally, keeled, acute-attenuate, tomentulose, tips reddish, glabrous or puberulent;

nut dark brown, often with light brown longitudinal stripes, subfusiform and acute to narrowly barrel-shaped, rarely distally rounded, (17-)20-30(-33) × 8-15 mm, glabrous.

subsessile, solitary;

cup hemispheric or cup-shaped, rarely deeper, 5-10 mm deep × 10-15 mm wide, enclosing only base of nut, scales thin and not tuberculate to strongly and irregularly tuberculate, particularly toward base of cup;

nut thin-walled, fusiform or subcylindric, 20-30 × 10-16 mm.
Cotyledons

connate.

distinct.
2n

= 24.

Quercus fusiformis

Quercus douglasii
Phenology Flowering spring. Flowering late winter–spring.
Habitat Hills, grasslands, scrublands, open woodlands, oak-juniper woodland, and margins of thorn scrub, often on limestone or deep calcareous loams, sometimes on granular sand or gravel Oak woodlands, margins of chaparral and grasslands
Elevation 0-1200 m (0-3900 ft) 0-1200 m (0-3900 ft)
Distribution
from FNA
OK; TX; Mexico (Coahuila, Nuevo León, and Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

The difficulty in distinguishing Texas populations of Quercus fusiformis from Q. virginiana is reflected in a variety of taxonomic treatments, including reducing Q. fusiformis to varietal rank under Q. virginiana. The latter disposition is problematic, however, because Q. fusiformis in northeastern Mexico is amply distinct from Q. virginiana and appears to be more closely related to Q. brandegei Goldmann, an endemic of Baja California, Mexico. Thus, here we assume that the intergradation of Q. virginiana and Q. fusiformis is a result of secondary contact, and is not primary clinal variation. Under this interpretation, Q. virginiana in typical form extends into Texas only as far west as the Brazos River drainage along the coast from there to the escarpment of the Edwards Plateau; most populations elsewhere are either intermediate between the two species or show greater affinity with Q. fusiformis. On the Edwards Plateau, the live oak populations are small trees forming rhizomatous copses (shinneries) and having mostly acute acorns.

Populations of live oak on deep sands in south Texas differ from typical Quercus fusiformis in having broader, more rounded leaves, often with the secondary veins somewhat impressed abaxially, and relatively blunt, barrel-shaped acorns. These characteristics suggest introgresion from the Mexican-Central American species Q. oleoides Schlechtendal & Chamisso, which in its typical form reaches north only as far as southern Tamaulipas, Mexico. The name Q. oleoides var. quaterna C. H. Muller has been applied to what is apparently a shrub form of one of these Q. fusiformis × Q. oleoides hybrids.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Populations of Quercus douglasii in coastal southern California and on the Channel Islands consist of small stands or solitary individuals often associated with Q. lobata and scrub oaks. Some doubt exists as to whether some or all of those populations are natural stands or are historical introductions near Native American settlements. Along the canyons of Santa Barbara County, putative hybrids between Q. douglasii and Q. dumosa are referred to Q. ×kinselae (C. H. Muller) Nixon. In the interior Coast Ranges of California are found numerous populations that are intermediate in form between Q. douglasii and Q. john-tuckeri (= Q. turbinella var. californica). This appears to be an area of secondary contact, and the two species remain distinct in nearby populations. Because of the widespread nature of the intermediates, following Tucker's extensive studies they can be conveniently referred to as the nothospecies Q. ×alvordiana Eastwood. The plants tend to be shrubs to small trees, with somewhat more spinose leaves than Q. douglasii and fruit similar to those of the latter species.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 3. FNA vol. 3.
Parent taxa Fagaceae > Quercus > sect. Quercus Fagaceae > Quercus > sect. Quercus
Sibling taxa
Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. douglasii, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robur, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii
Q. acerifolia, Q. agrifolia, Q. ajoensis, Q. alba, Q. arizonica, Q. arkansana, Q. austrina, Q. berberidifolia, Q. bicolor, Q. boyntonii, Q. buckleyi, Q. carmenensis, Q. chapmanii, Q. chihuahuensis, Q. chrysolepis, Q. coccinea, Q. cornelius-mulleri, Q. depressipes, Q. dumosa, Q. durata, Q. ellipsoidalis, Q. emoryi, Q. engelmannii, Q. falcata, Q. fusiformis, Q. gambelii, Q. garryana, Q. geminata, Q. georgiana, Q. graciliformis, Q. gravesii, Q. grisea, Q. havardii, Q. hemisphaerica, Q. hinckleyi, Q. hypoleucoides, Q. ilicifolia, Q. imbricaria, Q. incana, Q. inopina, Q. intricata, Q. john-tuckeri, Q. kelloggii, Q. laceyi, Q. laevis, Q. laurifolia, Q. lobata, Q. lyrata, Q. macrocarpa, Q. margarettae, Q. marilandica, Q. michauxii, Q. minima, Q. mohriana, Q. montana, Q. muehlenbergii, Q. myrtifolia, Q. nigra, Q. oblongifolia, Q. oglethorpensis, Q. pacifica, Q. pagoda, Q. palmeri, Q. palustris, Q. phellos, Q. polymorpha, Q. prinoides, Q. pumila, Q. pungens, Q. robur, Q. robusta, Q. rubra, Q. rugosa, Q. sadleriana, Q. shumardii, Q. similis, Q. sinuata, Q. stellata, Q. tardifolia, Q. texana, Q. tomentella, Q. toumeyi, Q. turbinella, Q. vacciniifolia, Q. vaseyana, Q. velutina, Q. viminea, Q. virginiana, Q. wislizenii
Synonyms Q. virginiana var. fusiformis Q. douglasii var. ransomii, Q. ransomii
Name authority Small: Bull. Torrey Bot. Club 28: 357. (1901) Hooker & Arnott: Bot. Beechey Voy. 9: 391. (1840)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Fabaceae, Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America

The species comparison tool is brought to you by:
Northwest Wildflowers